Field regulation for motor-generators.



0. E. EVELETH. FIELD REGULATION FOR MOTOR GENERATORS.

APPLICATION FILED MAR. 1, 1907.

PATENTED AUG. 25, 1908.

WsCnessw IUNXTED sTATEs PATENT. OFFICE.

CHARLES E. EVELETI-I, OF SOHENE GTADY, NEW YORK, ASSIGNOR TO 'GENERAL ELECTRIC COMPANY, A CORPORATION OF NEW YORK. v

v FIELD REGULATION FOR MoToR-sENERAroRs.

I T 0 all whom it may concern:

Be it known that I, CHARLES E. EVELETH, a citizen of the United States, residing at Schenectady, county of Schenect'ady,.State Such conditions arise, for instance, where the motor-generator is used for supplying current to a lighting circuit, the motor being driven by current takenfrom a trolley circuit, on which the voltage often fluctuates through wide ranges. Any change .in the power'voltage, of course, varies the speed of the motor and thus varies the generator voltage.

My invention aims .to regulate automatically not only the speed of the motor but the voltage of the generator, so that the combination of the two factors will result in keeping the latter voltage very steady irrespective of the fluctuations of the power voltage.

To this end,the invention consists in pro 'viding the field circuits of both the motor and the generator with regulators, preferablyf of the well-known Tirrill ty e shown for, example in patent to Tirrill, 0. 725,799, and

connecting across the lighting mains aifeleo tromagnetic switch controlling the operating coils of the two regulatorsf Oneregulator, that in themotor circuit, islari'a'nged. to cut out resistance when the generator voltage rises and thus s'loW down the' motor; while the regulator in thefield circuit of the generator is arranged to out in resistance at the same time, thus, tending to reduce the voltage on the lighting circuit. Two separate regulators may be" used; or, one regulator with -two sets of contacts.

The accompanying drawing is a diagram of circuits illustrating my invention.

The mains '1 represent a power circuit on which the voltage is liableto fluctuate considerably suoh a's a trolley line. suitable switch 2 enables these mains to be connected with the motor 3 of a motor-generator, whose generator end 4 is shown as supplying "current to a lighting circuit 5.- This is acommon arrangementyfor lighting waiting Specification of Letters "Patent. Application filed. March 1, 1907. Serial No. 359,9'bi3;

Patented Aug. 25, 1908.

rooms, sub-stations, fandthe like. In series with theffield coil 6 of the motor is 'a' resistance 7, around which is a shunt-controlled by a switch 8. In like manner, the. field coil 9 I of the generator is inseries with a resistance 10 around which is a shunt controlled by a switch '11. A spring 12tendsito keep the switch 8 open while a sp'ring 13 tends to keep the switch 11- closedrf Connected with .the movable 'lever-ofeach switch is'the arma: ture of an. electromagnet-" la 15. When the:

electromagnet 14' is energized it closes the switch 8 and short-circuit's -the resistance-7,

Similarly,'- when the magnet; ,15is energized it opens the switch 11 and cuts the resistance 10. In order to operatebotliswitchessimultaneously, their coilsf'fi'are both con nected across the lighting-mains 5,{ -and;are

adapted to be short-cireuit'ed'by a switch 16 controlledby a coilres'poi' siveato the line voltage. A resistance 18=-cuts .:down thefcure rent flowing through-the electromagnets 14 and 15 and the. switch 16.

In racti'cal operation,.the switch 16 continua y flutters by reason of the variations l stant agitation, .so to .s oak, whereby the in voltage inthe mains 5 The switches 8 and 10 are thereby kept a state of. confield currents of both" t e motor and generator are kept constantly varying in order to compensate for the changes in the voltage of the power circuit. The'result is that the voltage. in the lighting circuit will he kept practically constant under vai'iationsni I the power. voltage; amountinggevein to as;

much as a fluctuation from one half'to-iiull voltage in less than .asecond What I-cla1m as newand desire to secure i by Letters Pateh't-ofthd Unitedistatesji's l. The combinationfwith" a motor. .gn'erae; I

nor, of means responsive to the gem-stamentage for simultaneously varying thespeed'of the 1110 tor and the field St-the generato'rl 2. The combination as niotor'genera- 10o"- tor, of means responsive to-the generator at tage for simultaneously and-oppositely vary? ing the speed of the motor: andythe field strength of the generator.-.?#

3'. The combination: with a mealem tor, of means responsive toliegeherator voltage "for simultaneously "VBII'yI the; iic'ld gen strength of both the: meter and.

e motor and tor, of an electromagnetic switch controlling the field strength of the motor end, a second electromagnetic switch controlling the field strength of the generator end, and means for operating both switches simultaneously.

6. The combination with a motor-generator, of an electromagnetic switch controlling the field strength of the motor end, a second electromagnetic switch controlling the field strength of the generator end, and means for operating both switches simultaneously, said means being responsive to changes in the generator voltage.

7. The combination with a motor-generator, of regulators for the field strength of both ends'thereof, and an electromagnetic ositoly vary-.

and oppositely actor, of resistances'in series with the field coils of each. end thereof, a shunt around each resistance, and means controlled by the generator Voltage for simultaneously opening one shunt and closing the other, and vice versa.

9. The combination with a motor-generator, of electric re ulating devices for the fields of both ends fiiereof, said devices being connected across the mains taking current from the generator end, a normally open shunt around said devices, and a no-voltage switch for closing said shunt.

In witness whereof, I have hereunto set my hand this 23rd day of February, 1907f CHARLES E. EVELETIL Witnesses:

EDGAR D. DICKINSON, WILLIAM R. CHAMBERS. 

